1. Field of the Invention
This invention relates to an apparatus and a method for the topical targeted delivery of a substance to the internal body tissues and walls of a patient's upper airway.
2. Brief Description of the Prior Art
The endotracheal tube and the tracheostomy tube are life-support devices commonly used to secure and protect the upper airway of a patient and to permit safe and proper life-sustaining ventilation and oxygenation of a patient's lungs. An endotracheal tube is made of any suitable material such as, for example, a resinous plastic material, metal or rubber and may be made of an opaque, translucent or transparent material. The material may be flexible or rigid. Endotracheal tubes may be manufactured using extrusion or other techniques well known by those skilled in the art. Generally, an endotracheal tube is placed through a patient's nose or mouth and down into the trachea (windpipe). A tracheostomy tube is similar in design and function to an endotracheal tube, however, the major difference being that a tracheostomy tube is shorter in length and is placed by way of a surgical incision in the patient's neck directly into the larynx (voicebox) or trachea.
Endotracheal and tracheostomy tubes are used throughout the world in a variety of clinical settings, including for example, patients receiving general anesthesia and critically ill patients requiring life-support. Several problems and potential hazards, however, are associated with the use of endotracheal or tracheostomy tubes. One important problem associated with these tubes is that they are irritating to the unanesthetized mucosal lining of the nose, mouth, pharynx (throat), larynx and trachea. For this reason, these tubes can produce violent coughing and gagging when inserted into or when present in the upper airway of awake, semi-awake or lightly anesthetized patients. Coughing and gagging can lead to several undesirable and dangerous outcomes. The patient's violent movements associated with coughing and gagging can result in the patient inadvertently and prematurely coughing or pulling out the endotracheal tube, or in the patient pulling out the patient's intravenous lines or pulling off of vital monitors. The coughing may be so violent that it necessitates the anesthesia care team to prematurely remove the endotracheal or tracheostomy tube. This premature removal of the tube can lead to life-threatening or health-threatening conditions, such as for example, laryngospasm with accompanying total airway obstruction or aspiration of vomitus into the lungs. Additionally, violent coughing may threaten or damage delicate surgical repairs, such as for example, surgery on the tiny bones of the middle ear or on the fragile structures of the eye.
The irritating effect of the endotracheal tube or tracheostomy tube also frequently produces severe and life-threatening or health-threatening elevations in blood pressure, heart rate, intracranial pressure and life-threatening bronchospasm in patients with a history of asthma or other lung diseases. Another hazard of using endotracheal or tracheostomy tubes is that they can mechanically traumatize or abrade the sensitive mucosal lining of the upper airway during placement of the tube, particularly in patients in whom the tracheal intubation was technically difficult and required multiple attempts, or in patients requiring extended or prolonged tracheal intubation. This can lead to significant swelling and inflammation of the airway. Subsequent to the removal of the tube, this airway swelling or inflammation can lead to partial or substantially total airway obstruction resulting in damage to the brain or heart from insufficient oxygen.
A number of patents disclose endotracheal or tracheostomy tubes and methods for promoting ventilation or respiration, but none teach or suggest the improved results of the device and process of the present invention.
U.S. Pat. No. 4,327,721 discloses an endotracheal tube including an expandable cuff and an annular chamber circumferentially extending around the endotracheal tube. This patent states that the outer walls of the annular chamber have spaced openings through which topical agents are dispensed to the mucosal area of the trachea.
U.S. Pat. No. 3,173,418 discloses an endotracheal tube having an internal cuff and a multiperforated external cuff. This patent states that anesthetic fluid is injected into the space between the external and internal cuffs and is sprayed through the holes of the external cuff allowing anesthetic to be delivered around the surface of the external cuff to the mucous membranes of a patient's trachea.
U.S. Pat. No. 4,230,108 discloses a flexible esophageal tube having inflatable cuffs, and a ventilation tube. This patent states that the esophageal tube and the ventilation tube define common perforations in the area between the cuffs for ventilating the lungs.
In spite of these prior art disclosures, there remains a very real and substantial need for an apparatus and a method for improving a patient's tolerance of an endotracheal or tracheostomy tube in the patient's upper airway.